<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>条件渲染</title>
  <script src="./vue.js"></script>
</head>
<body>
  <div id="app">
    <div v-if="show">
      用户名：<input key="userName"/>
    </div>
    <div v-else>
      邮箱名：<input key="emialName"/>
    </div>
  </div>

  <script>
    var vm = new Vue({
      el: "#app",
      data: {
        show: false
      }
    });
  
  </script>
</body>
</html>